对于列的每个值，将该值除以另一列中具有相同序列的行数（使用 R 计算多映射读取）

Question

这是我的数据集的一部分：

    structure(list(V1 = c("t00000406", "t00000517", "t00000519", 
"t00000589", "t00000589", "t00000598", "t00000804", "t00000938", 
"t00001008", "t00001156", "t00001156", "t00001156", "t00001165", 
"t00001165", "t00001165", "t00001265", "t00001265", "t00001265", 
"t00001511", "t00001562", "t00001562", "t00001599", "t00001703", 
"t00001703", "t00001703", "t00001710", "t00001710", "t00001710", 
"t00001710"), V2 = c(617L, 445L, 439L, 357L, 357L, 352L, 234L, 
192L, 177L, 151L, 151L, 151L, 149L, 149L, 149L, 138L, 138L, 138L, 
114L, 111L, 111L, 108L, 101L, 101L, 101L, 101L, 101L, 101L, 101L
), V4 = c("piR-hsa-3546", "piR-hsa-3454", "piR-hsa-3546", "piR-hsa-6909", 
"piR-hsa-6908", "piR-hsa-3454", "piR-hsa-3454", "piR-hsa-3454", 
"piR-hsa-3454", "piR-hsa-31261", "piR-hsa-14100", "piR-hsa-14099", 
"piR-hsa-28592", "piR-hsa-6592", "piR-hsa-6591", "piR-hsa-14099", 
"piR-hsa-31261", "piR-hsa-14100", "piR-hsa-6909", "piR-hsa-16270", 
"piR-hsa-16271", "piR-hsa-620", "piR-hsa-31261", "piR-hsa-14100", 
"piR-hsa-14099", "piR-hsa-14098", "piR-hsa-14100", "piR-hsa-14099", 
"piR-hsa-31261"), V6 = c("CTGTTAACCGAAAGGTTGGTGGT", "CACGTGTTAGGACCCGAAAGA", 
"CGGCTGTTAACCGAAAGGTTGGTGGT", "GTTTCCGTAGTGTAGTGGTCATC", "GTTTCCGTAGTGTAGTGGTCATC", 
"ACGTGTTAGGACCCGAAAGA", "CGTGTTAGGACCCGAAAGA", "TGTTAGGACCCGAAAGA", 
"CGCACGTGTTAGGACCCGAAAGA", "TCCCTGGTGGTCTAGTGGTTAGGATTCGGC", 
"TCCCTGGTGGTCTAGTGGTTAGGATTCGGC", "TCCCTGGTGGTCTAGTGGTTAGGATTCGGC", 
"GTAGTCGTGGCCGAGTGGTTAAG", "GTAGTCGTGGCCGAGTGGTTAAG", "GTAGTCGTGGCCGAGTGGTTAAG", 
"TCCCTGGTGGTCTAGTGGTTAGGATT", "TCCCTGGTGGTCTAGTGGTTAGGATT", "TCCCTGGTGGTCTAGTGGTTAGGATT", 
"GTTTCCGTAGTGTAGTGGTCATCACGTTCGCC", "CTGAGGGTCCAGGGT", "CTGAGGGTCCAGGGT", 
"CGTAGTTCCGACCATAAACGATGCC", "TCCCTGGTGGTCTAGTGGTTAGGATTC", "TCCCTGGTGGTCTAGTGGTTAGGATTC", 
"TCCCTGGTGGTCTAGTGGTTAGGATTC", "TCCCTGGTGGTCTAGTGGTTAGGAT", "TCCCTGGTGGTCTAGTGGTTAGGAT", 
"TCCCTGGTGGTCTAGTGGTTAGGAT", "TCCCTGGTGGTCTAGTGGTTAGGAT")), row.names = c(NA, 
-29L), class = c("tbl_df", "tbl", "data.frame"))

我想 "mutate" V2 列的每个值除以一个值，该值由数据中存在的相同 "sequence" 的次数计算得出。 ->

序列GTAGTCGTGGCCGAGTGGTTAAG存在3次

    nrow(filter(my_data,V6=="GTAGTCGTGGCCGAGTGGTTAAG"))
[1] 3

结果：

filter(pir_onehun,V6=="GTAGTCGTGGCCGAGTGGTTAAG") %>% mutate(V2=V2/nrow(filter(pir_onehun,V6=="GTAGTCGTGGCCGAGTGGTTAAG")) )
# A tibble: 3 x 4
  V1           V2 V4            V6                     
  <chr>     <dbl> <chr>         <chr>                  
1 t00001165  49.7 piR-hsa-28592 GTAGTCGTGGCCGAGTGGTTAAG
2 t00001165  49.7 piR-hsa-6592  GTAGTCGTGGCCGAGTGGTTAAG
3 t00001165  49.7 piR-hsa-6591  GTAGTCGTGGCCGAGTGGTTAAG

我想用 bind_rows 将结果附加到一个新的数据框，但它必须是另一种更 "tidy" 的方式。

感谢您的宝贵时间

Answer 1

df %>% group_by(V6) %>% mutate(V2 = V2 / n())

完成任务。首先我们按顺序分组，然后除以这个组的大小，n().

对于列的每个值，将该值除以另一列中具有相同序列的行数（使用 R 计算多映射读取）

For each value of a column divide that value by the number of rows that have the same sequence in another column (counting multimapped reads with R)

r

dataframe

tibble